Modern wireless communication devices continue to evolve, offering an increasing array of capabilities, and are now virtually ubiquitously used by consumers to access a variety of data intensive services via wireless networks. For example, wireless communication devices are used to access a wide array of Internet services, such as audio/video streaming services, web browsing, and the like. The exponential increase in demand on wireless networks to support such data intensive services has placed a demand on wireless network operators to upgrade their wireless networks to support both increased data capacity and faster data rates. As such, ongoing efforts are being made to develop and deploy improved radio access technologies (RATs) capable of supporting higher throughput for data transmitted via wireless networks to satisfy the demand for data services from modern wireless communication devices.
Some modern cellular RATs, such as Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) Release 10 and beyond, also referred to as LTE-Advanced (LTE-A), address the increased demand for data intensive services by implementing a technique known as carrier aggregation, in which radio frequency bandwidth available for communication can be extended through the aggregation of multiple component carriers (CCs). In this regard, rather than using a single carrier to support communication between a device and a wireless network, carrier aggregation uses multiple component carriers in parallel such that radio frequency bandwidth for data transmissions to and/or from a wireless communication device can be increased through the aggregation of multiple component carriers for conveying data transmissions.
While carrier aggregation techniques provide improved throughput for supporting data intensive services, there is a limited amount of licensed radio frequency spectrum available for LTE wireless network operators to use for carrier aggregation purposes. In this regard, wireless network operators of LTE and other cellular RATs are traditionally allocated (e.g., licensed) one or more defined radio frequency bands within the radio frequency spectrum for use to support cellular transmissions. This limited availability of licensed radio frequency spectrum available to wireless network operators is likely to make it increasingly difficult in the future for wireless network operators to accommodate the ongoing exponential growth in data traffic for advanced wireless communication devices. As such, wireless network operators and wireless communication device manufacturers are looking to the use of unlicensed radio frequency bands to accommodate additional data traffic growth. In this regard, unlicensed radio frequency bands, such as the 2.4 Gigahertz (GHz), 5 GHz, and other industrial, scientific, and medical (ISM) radio frequency bands, are free to use without a license. As such, LTE and other cellular RATs can be extended to use unlicensed radio frequency bands to expand their capacity. For example, unlicensed LTE (LTE-U) allows for the deployment of LTE in unlicensed radio frequency spectrum, e.g., for carrier aggregation purposes. However, given that unlicensed radio frequency spectrum is free to use, unlicensed radio frequency spectrum cannot match the quality of service provided by licensed radio frequency spectrum due to the unpredictability of interference from competing uses of the unlicensed radio frequency spectrum, such as from Wi-Fi devices. Uplink data that is sensitive to throughput, delay, latency, and/or other quality of service requirements can be particularly sensitive to the impact of interference in the unlicensed radio frequency spectrum. Accordingly, uplink transmission in the unlicensed radio frequency spectrum, such as for LTE-U capable systems, continues to be problematic.